SUSTAINABLE DRAINAGE SYSTEMS 2019 Suds 3 INTRODUCTION to AGGREGATE INDUSTRIES
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SUSTAINABLE DRAINAGE SYSTEMS 2019 SuDS 3 INTRODUCTION TO AGGREGATE INDUSTRIES Aggregate Industries are at the frontline of the construction and infrastructure industries, CONTENTS producing and supplying an array of construction materials. With over 330 sites and more than 4,100 Introduction 4 - 5 dedicated employees, we’re home to everything The Need for Sustainable Drainage Solutions 6 - 7 from aggregates, asphalt, ready-mixed concrete Types of SuDS 8 - 9 and precast concrete products. Product and Applications 10 - 19 In addition to producing, importing, exporting and Example Solutions 20 supplying construction materials we also offer national Designing SuDS Pavements 22 - 31 road surfacing and contracting services. Our complete Construction, Installation and Maintenance 32 - 39 range of products will help you work sustainably, safely, professionally and profitably. It’s all of this that puts us Case Studies 40 - 47 at the heart of construction. We are a proud member of LafargeHolcim, which is the APPENDICES leading global building materials and solutions company Technical Specifications 50 - 60 with around 80,000 employees in over 80 countries. It holds leading positions in all regions with a balanced Guidance and Legislation 61 portfolio of developing and mature markets. Aggregate Industries The Complete Service 62 Our Sustainable Drainage System (SuDS) solutions range offers a comprehensive choice of options to both reduce flood risk and to control and minimise pollution before it enters our watercourses, enabling us to use water in a more sustainable and environmentally beneficial way. 4 SuDS OUR SuDS SOLUTIONS WORK BY SuDS WITH TEMPORARILY RETAINING AND SLOWLY RELEASING RAINFALL AGGREGATE INDUSTRIES BACK INTO THE WATERWAYS IN A Ever-changing weather systems, increasing CONTROLLED MANNER urbanisation and rapid run-off have put a tremendous strain on conventional storm water drainage systems. This has resulted in sewers and culverts becoming overloaded, causing floods and contaminating natural waterways. Sustainable Drainage Systems (SuDS) provide an alternative approach to traditional drainage systems. They mitigate many of the adverse impacts of storm water run-off on the environment in terms of both volume and pollutants. Aggregate Industries have been at the forefront of research work regarding materials for use in SuDS solutions. Initially as part of the research team contributing to PPR 482-A pilot scale trial of reservoir pavements for Drainage Attenuation published by the Transport Research Laboratory (TRL) investigating the use of SuDS solutions. This subsequently contributed to HD221/18 within the Design Manual for Roads and Bridges. More recently we also contributed to CIRIA’s C753 document – “The SuDS Manual” published in December of 2015. Our SuDS solutions work by temporarily retaining and slowly releasing rainfall back into the waterways in a controlled manner. This helps prevent floods, while allowing natural processes to break down pollutants which would otherwise impact further downstream. SuDS became a legal consideration for all new developments per the Flood & Water Management Act 2010 and was integrated into Building Regulations in 2015. 6 SuDS SuDS 7 Flood potential Pollution Climate changes As development increases, so do run-off Traffic, hard surfaces and increased run-off It is generally accepted that the UK’s climate speeds and volumes. Their rapid delivery can increase the risk of pollutants, which are is changing and that our weather is becoming into the local water courses can cause literally washed off the streets into the water more extreme. Paradoxically, in the short THE NEED FOR flooding downstream, resulting in danger catchment, contaminating the downstream term, it is not the overall levels of rainfall that to life and damage to property, or erosion water supply. influence the need for sustainable drainage, and destruction of natural habitats. but the ferocity and frequency of the single rainfall events that may cause flooding. SUSTAINABLE These, combined with on-going development, DRAINAGE SOLUTIONS add to the necessity for SuDS solutions. Natural Agricultural Suburban Inner City 5% 30% 70% 95% run off run off run off run off 95% infiltration 70% infiltration 30% infiltration 5% infiltration Infiltration and run-off Naturally vegetated, rural ground is permeable and has the capacity to absorb high levels of rainfall through its surface -’infiltration’ - and to release the infiltrated water gradually into natural water courses. Development of this ground can greatly reduce permeability by the introduction of hard surfaces - asphalt, paving concrete and the compaction caused by plant or vehicular movement. Less water infiltrates the ground and more water runs off the surface, more rapidly. Traditionally, to avoid local flooding, surface run-off has been drained into underground pipe systems and delivered elsewhere into the water catchment area. Key benefits } Storm water management - high permeability and drainage capacity } Environmental management - minimises urban impact on natural water cycle } Reduces costs as part of a Sustainable Drainage Systems SuDS } Available with integral colour to offer decorative and functional hard landscaping opportunities } Eliminates the need for retention ponds } Offers potential space saving for efficient land development } Mitigates surface pollutants } Reduces glare from wet pavement } No standing water, lessens risk of hydroplaning For any queries on the Aggregate Industries SuDS offering, please contact us at [email protected] 8 SuDS SuDS 9 TYPES OF SuDS ENGINEERED OR HARD LANDSCAPING Engineered SuDS can be split into two different types: } Permeable surfaces } Mix of permeable and impermeable materials THE KEY SuDS PRINCIPLES 1. SOURCE CONTROL Sustainable drainage systems control surface water run-off as close to its origin as possible. This is termed ‘source control’. This minimises changes in the volume and rate of surface run-off from developed sites and thereby minimises flood risk and other environmental damage. Additionally, SuDS may offer an element of pollution control as well as ‘attenuation’ – where infiltrated water is stored before its controlled release. PERVIOUS SURFACES 2. MANAGEMENT TRAIN Pervious surface systems include permeable or porous surfaces to car parks, roads, hardstandings and pedestrian areas. Any area These levels of control and treatment result from a series of covered by a hard surface can be turned into a permeable surface techniques (‘management train’) that integrate with one another and incorporated into a sustainable drainage design. to gradually reduce levels of pollution, volume and flow rate prior to discharge. Infilta block (page 14) and SuperDrainasphalt (page 15) are products typical of these types of systems and when incorporated into an 3. WATER QUALITY urban SuDS development, they enhance the urban landscape. A Removing pollution from run-off is an important part of SuDS study by HR Wallingford determined that pervious surfaces are one design. The use of SuDS to control pollution and replace oil of the most effective and space efficient methods of incorporating separators is highlighted in the most recent edition of Pollution SuDS into developments designed to comply with Planning Policy Prevention Guideline PPG 3 published by the Environment Guidance 3, requiring a high density of housing to be provided on Agency (2006). new developments. 4. AMENITY AND BIODIVERSITY Even if there is contamination, the use of SuDS is still possible } Many brownfield sites are only marginally contaminated providing that care is taken in its design to avoid mobilising pollution and the contamination may be in a non-leachable form. Trees are an important element in the biodiversity of urban areas into the surface or groundwater. The use of shallow SuDS such as Often, this does not pose a significant risk to groundwater and improve amenity by providing enhanced aesthetics, cooling the Aggregate Industries’ systems should limit the need for the deep when SuDS are used. and shading. Aggregate Industries’ SuDS methods can be designed excavations that are commonly required with conventional drainage. to protect and enhance the health of existing and new trees by protecting the roots systems and providing irrigation and aeration All contaminated sites are different and the level of contamination GREEN AND SOFT LANDSCAPING to the soil. can vary from slight to high. Therefore, each site should be Swales, ponds, wetlands and similar methods are classed as assessed on its own merits considering the following: green/soft landscaping and many SuDS schemes involve their use. The key considerations can be summarised as follows: The Charcon systems provided by Aggregate Industries can be } Prevent mobilisation of contamination and its transportation used as part of soft landscaping systems. It is bad SuDS practice } Water quantity to receiving waters. This means infiltration cannot be used if to direct untreated run-off into ponds or wetlands as it will reduce } Water quality soils contain contaminants in a form that can be leached out. their contribution to biodiversity and landscape value. } Amenity benefit If such soils are present, then infiltration may still be used if it occurs below the base of the contaminated soils. } Prevent the flow of contaminated groundwater into the SuDS solution. Such flow is unlikely with the shallow Aggregate Industries systems. IMPERMEABLE SURFACES } Use features that minimise excavation and